Fluid valves control the flow of fluid from one location to another. When the fluid valve is in a closed position, high pressure fluid on one side is prevented from flowing to a lower pressure location on the other side of the valve. The pressure differences between an inlet and an outlet of the control valve, along with a tortuous flow path through the control valve, produce turbulent fluid flow downstream of the control valve, which causes unwanted and potentially harmful noise.
In an attempt to reduce noise, multi-port cages or trims have been used in some regulators to reduce the pressure drop across the cage and to smooth downstream flow. In these cases, a trim assembly may be used that includes a cage with a plurality of openings. The openings may be sized and shaped to characterize fluid flow through the trim assembly. In one example, the openings characterize the fluid flow by reducing noise.
Often the openings are quite small and may become easily clogged. As a result, manufacturers typically recommend filtering the process fluid before it enters the regulator to remove impurities that may clog the openings. However, even with manufacturer recommendation, users often do not filter the process fluid, which leads to clogged openings. When enough openings become clogged, the regulator will no longer function properly and the clogged openings may lead to a potentially dangerous overpressure condition because fluid is prevented from flowing. This overpressure condition in some cases may cause the regulator to fail, sometimes catastrophically.